Effect of Modulating Spin-Coating Rate of TiO₂ Precursor for Mesoporous Layer on Hysteresis of Solar Cells with Polar CH₃NH₃PbI₃ Perovskite Thin Film

Figure 1

3D surface topography AFM images of the CH₃NH₃PbI₃ perovskite films with mp-TiO₂/bl-TiO₂/FTO structure which applied DC biases voltage and AC voltage groups are (a) (0 V, 0 V), (b) (~8 V, 0 V), (c) (~8 V, +3 V), and (d) (~8 V, +6 V). (a), (b), (c), and (d) are the same substrate and the same position. In order to see clearly, (c) and (d) are the enlargement of the center of (a) and (b).

(a)

(b)

(c)

(d)